fwunixref

Unix/Linux Command Reference .com

File Commands System Info

ls – directory listing date – show the current date and time

ls -al – formatted listing with hidden files cal – show this month's calendar
cd dir - change directory to dir uptime – show current uptime

cd – change to home w – display who is online
pwd – show current directory whoami – who you are logged in as

mkdir dir – create a directory dir finger user – display information about user
rm file – delete file uname -a – show kernel information

rm -r dir – delete directory dir cat /proc/cpuinfo – cpu information
rm -f file – force remove file cat /proc/meminfo – memory information

rm -rf dir – force remove directory dir * man command – show the manual for command
cp file1 file2 – copy file1 to file2 df – show disk usage

cp -r dir1 dir2 – copy dir1 to dir2; create dir2 if it du – show directory space usage
doesn't exist free – show memory and swap usage

mv file1 file2 – rename or move file1 to file2 whereis app – show possible locations of app
if file2 is an existing directory, moves file1 into which app – show which app will be run by default

directory file2 Compression
ln -s file link – create symbolic link link to file
touch file – create or update file tar cf file.tar files – create a tar named
file.tar containing files
cat > file – places standard input into file tar xf file.tar – extract the files from file.tar
more file – output the contents of file tar czf file.tar.gz files – create a tar with
head file – output the first 10 lines of file Gzip compression
tail file – output the last 10 lines of file tar xzf file.tar.gz – extract a tar using Gzip
tail -f file – output the contents of file as it tar cjf file.tar.bz2 – create a tar with Bzip2
grows, starting with the last 10 lines compression
tar xjf file.tar.bz2 – extract a tar using Bzip2
Process Management gzip file – compresses file and renames it to
file.gz
ps – display your currently active processes gzip -d file.gz – decompresses file.gz back to
top – display all running processes file
kill pid – kill process id pid
killall proc – kill all processes named proc * Network
bg – lists stopped or background jobs; resume a
stopped job in the background

fg – brings the most recent job to foreground ping host – ping host and output results
fg n – brings job n to the foreground
whois domain – get whois information for domain
dig domain – get DNS information for domain
File Permissions dig -x host – reverse lookup host
wget file – download file
chmod octal file – change the permissions of file wget -c file – continue a stopped download
to octal, which can be found separately for user,
group, and world by adding:
● 4 – read (r)
● 2 – write (w) Installation
● 1 – execute (x)
Examples: Install from source:
chmod 777 – read, write, execute for all ./configure
chmod 755 – rwx for owner, rx for group and world make
For more options, see man chmod. make install
dpkg -i pkg.deb – install a package (Debian)
SSH rpm -Uvh pkg.rpm – install a package (RPM)

ssh user@host – connect to host as user Shortcuts
ssh -p port user@host – connect to host on port
port as user Ctrl+C – halts the current command
ssh-copy-id user@host – add your key to host for Ctrl+Z – stops the current command, resume with
user to enable a keyed or passwordless login fg in the foreground or bg in the background
Ctrl+D – log out of current session, similar to exit
Searching Ctrl+W – erases one word in the current line
Ctrl+U – erases the whole line
grep pattern files – search for pattern in files Ctrl+R – type to bring up a recent command

grep -r pattern dir – search recursively for !! - repeats the last command
pattern in dir
exit – log out of current session
command | grep pattern – search for pattern in the
output of command
locate file – find all instances of file * use with extreme caution.